Light diffusing bodies have been conventionally used in various optical applications, including transmission type screens.
A light diffusing body to be used in the transmission type screens requires the properties that the light source of a projector behind the screen is not directly seen through and that the brightness of the whole screen is not reduced. There have been proposed a light diffusing plate (refer to Patent document 1) and a transmission type screen (refer to Patent document 2), in which an optimal balance between the transmission and diffusion of light was taken into account.
In the transmission type screen, in which the projector side is seen through (transmissible), the projector is installed not at a front position but at an oblique position to prevent that the light source is seen directly.
However, even the projector is installed at an oblique position, the light source may be seen when coming closer to the screen. Even for the see-through transmission type screens, if they have a high haze, a project may be installed at a front position. In this case, the light source may be visible.
These cases cause the phenomenon that the light source seen through the light diffusing body looks red, yellow, blue etc. It then caused the problem that the colored light source overlaps the images displayed on the screen, and that the images look as colored.
[Patent document 1] Japanese Patent Unexamined Publication (KOHO) No. 1989-269901 (Prior art)
[Patent document 2] Japanese Patent Unexamined Publication 2005-024942 (KOHO) (Object to be achieved by the invention)